The invention relates to a section for swimming pool rollable cover, said section being of the type with open compartments comprising, longitudinally, two complementary assembly shapes permitting a limited articulation of two assembled sections, each shape being equipped at each end with a plug for tightly closing the compartments.
It is known that swimming pool covers are particularly used to limit pollution, to save on the heating of the water and to prevent risks of accidents. Amongst the existing types of covers, automatic rollable covers offer the best guarantees: they are composed of a rolling shutter made up of plastic strips which slide over the surface of the water and are combined to a hand- or electric-operated winding device.
In order to be more efficient, the covers must keep a minimum clearance between the walls of the pool and the sides of the shutter therefore it is imperative for the strips to be fixed one to the other in such a way that it is impossible for them to shift sideways, which could cause jamming of the cover during operation. In the currently known covers, the strips are interconnected in the longitudinal direction by a complex fastening of the connecting shapes which is not altogether satisfactory because of its complexity, of the risks of breaks, and because the connecting shapes as well as the fastening method allow the pool water to filter through to the top of the cover, as the tightness problems existing with an articulated assembly and with fastening means preserving the articulation, are yet to be solved.
It is the object of the present invention to overcome the disadvantages of the known systems and to propose a section which guarantees a straightness of edges to the cover without the possibility of one section moving sideways with respect to the others and which also achieves perfect tightness.
This object is reached due to the presence of end plugs provided for sealing off the end of the sections and to give them a new function: indeed, according to the invention, the end plugs cooperate with the connecting shapes in order to lock the assembly in the longitudinal direction without impairing the articulation.
To this effect, the plug according to the invention generally comprises a part which is used for closing off the compartments inside the section, and a part which projects towards the connecting shape of the section and acts as a longitudinal bearing for the complementary connecting shape of the next section. The presence of a plug at each end of a section thus ensures the longitudinal immobilizing of the next section.
It is found however that sections produced by extrusion are in general far from having the strict dimensions of end openings that they should have, and that, as a result, perfect tightness cannot always be guaranteed with the aforedescribed plug means, which is itself molded with very precise tolerances, and may not adapt to the openings of the section compartments.
For this reason, it has been decided to provide an extra plug for tightness. The plugs known heretofore, such as in cork, are not satisfactory because they are difficult to fit in and they are not completely hermetical when the section is not round; moreover, they deteriorate after a while in contact with pool water. They also impose having a large stock of various sizes and shapes to suit all types of sections.
According to the invention, waterproofing plugs, in closed-cell foam of synthetic material, of dimensions greater than the dimensions of the sections to be sealed off, are adhesively fixed in the openings. Due to the resiliency of such a material (of the type: neoprene foam, or nitril foam, or foams of other cellular rubbers, known under the designations EPDM, EPT, SBR, etc.), which is forced into the cavity, the plug is in full resting contact against the walls of the section to be sealed off.
For ready introduction of said plug into the cavity, the invention proposes to use an adhesive which is very fluid (oil-like) before drying, into which the plug is dipped before being inserted, said adhesive acting then as a lubricant. An acrylo-nitril adhesive (containing an acrylic substance in fluid solution compatible with the neoprene and any other rubbers used) has been found to be very suitable.
According to another aspect of the invention, said plug can be replaced by or accompanied with a plug of hard-setting foam which is introduced into the cavity in the soft state and left to harden therein.
In an advantageous embodiment the connecting shapes are of circular cross-section for the male shape, and of cross-section in arc of circle for the female shape, the male shape being hollow at least at its ends to receive a complementary cylindrical projection formed on the plug of the next section and comprising means of longitudinally immobilizing the female shape.
Indeed, according to this particular assembling design, the cover is virtually waterproof in the connecting points and play is insignificant widthwise of the strips, which permits a fine and easy end-of-course adjustment of the operating device. In addition, the cylindral projection locks the assembly in position in the width of the strips, which is another object of the invention.
The section according to the invention is obtained by extrusion. The male cylindrical connecting shape is then entirely hollow. To use it as a flat and to improve waterproofness of the cover, it should also be tightly closed off, and it is provided to this effect with two inner plugs formed in the vicinity of its ends.
Advantageously, the end plugs are constituted by a base-plate provided with one or more projections for hermetically closing the compartments, and, on the side of the female connecting shape, it comprises a cylindrical projection designed to be received by the male connecting shape of the next section. The projections used for closing off the compartments are adhesively fixed thereto.
In order to take advantage of the hot-house effect, the upper face of the section is translucid or transparent. But to prevent algae from spreading into the pool water, the lower face of the section is opaque, in actual fact, it is black, in order to help the absorption of the solar radiations. This bicolorism is obtained in the mass, during extrusion, in preference to the use of a black paint which would badly withstand the chemical agressions of the pool water and of its various additives.